1. Field of the Invention
The present invention relates to a tape feeder and a method of automatically setting a tape initial position by the tape feeder, and more particularly, to a tape feeder, which transfers a tape in which components are received therein, separates a top cover from the tape, and discharges the separated top cover so that the components can be picked up by a component mounter, and a method of automatically setting a tape initial position by the tape feeder.
2. Description of the Related Art
A tape feeder supplies components to a component mounter, such as a chip mounter. Then, the chip mounter mounts the components, e.g., semiconductor chips, in certain positions on a printed circuit board. That is, the tape feeder supplies various kinds of components in various ways to the chip mounter and the chip mounter mounts them on the printed circuit board using a suction nozzle operated by a robot.
The way of supplying the components varies according to the operating conditions and the characteristics of the components. For example, large components are supplied by being carried on a tray but small components do not require a tray.
In particular, very small components are frequently lost or damaged during mounting, and thus, they require a special tape feeder. Accordingly, as shown in FIG. 1, a tape 2, which has a plurality of receiving spaces 2a aligned thereon such that a plurality of components 5, e.g., semiconductor chips, are received in the receiving spaces 2a and covered and sealed by a top cover 2b, and also has a plurality of tape holes 2c formed on a side thereof at predetermined intervals, is transferred to a component mounter by a tape feeder.
The tape 2, to which the small-sized components are attached at the predetermined intervals, is wound around a roll, and the tape feeder pulls the tape 2 from the roll and at the same time removes the top cover 2b, which covers the components 5 retained by the tape 2. A suction nozzle operated by a robot lifts the components from the tape (from which the top cover has been removed) and moves the components to the predetermined positions on the printed circuit board.
FIG. 2 is a perspective view of a conventional tape feeder for a component mounter disclosed in Korean Patent Publication No. 2002-0047860. Referring to FIG. 2, a tape feeder 10 includes a frame 11, a tape transferring unit 20 for transferring a tape 2 at a predetermined pitch, a top cover discharging unit 40 for discharging a top cover detached from the tape, a driving unit 50 for simultaneously or separately driving the tape transferring unit 20 and the top cover discharging unit 40, and a shutter unit 70 for preventing electronic components from being separated.
The tape transferring unit 20 includes a sprocket 22, which has teeth inserted into tape holes 2c of the tape 2 and transfers the tape 2 at a predetermined pitch. The tape 2 is engaged with the sprocket 22 by a tape guide 71, and a top cover 2b is discharged upwardly past the tape guide 71.
The sprocket 22 is rotated by a transfer worm gear 57 and a transfer worm wheel 58 meshing with the transfer worm gear 57, which are driven by a driving motor 52. In this case, a ratchet 31 and a stopper 32 prevent the reverse rotation of the sprocket 22.
Also, the tape feeder 10 includes a rotational angle sensing unit 80, which is installed on a frame 11 and senses a rotational angle of the sprocket 22. The rotational angle sensing unit 80 includes an encoder 81 and a sensor 82 for sensing a value of the encoder 81.
The top cover discharging unit 40 includes a first discharge gear 41 and a second discharge gear 42. The first discharge gear 41 and the second discharge gear 42 meshing with each other receive the top cover 2b therebetween and discharge the top cover 2b. 
To be more specific, a discharge intermediate gear 59 rotates due to a driving force of the driving motor 52, and accordingly, a discharge worm gear 62 is driven. A discharge worm wheel 63 is driven due to the rotation of the discharge worm gear 62, and a second roller 64 and a first roller 65 rotate accordingly. Then, the first discharge gear 41 and the second discharge gear 42 rotate simultaneously, resulting in the discharge of the top cover 2b. 
The second discharge gear 42 is connected to one end of a second discharge lever 67, and the other end of the second discharge lever 67 is fixed an end portion of the frame 11. A second discharge lever spring 67a is installed on the other end of the second discharge lever 67 and elastically biases the second discharge gear 42 toward the first discharge gear 41.
Such a conventional tape feeder 10 using the sprocket 22 suffers from the following problems.
First, since the transfer worm gear 57 is used to rotate the sprocket 22, a considerable space for the transfer worm gear 57 is required.
Second, to pick up the components 5 at precise and flat positions, the tape 2 needs to move linearly in a predetermined section. However, since the sprocket 22 rotates circularly, linear motion stability of the tape 2 receiving the very small electronic components is difficult.
Third, the tape feeder 10 uses the sprocket 22 to feed the tape 2, the transfer worm gear 57 and the transfer worm wheel 58 to drive the sprocket 22, the ratchet 31 and the stopper 32 to prevent the reverse rotation of the carrier tape 2, and the rotational angle sensing unit 80 to sense the rotational angle of the sprocket 22. Accordingly, for example, to transfer two strips of tape, two sets of the above elements are required. As a result, when multiple strips of tape are transferred by one tape feeder, the tape feeder must be large and the manufacturing costs thereof are high.
Fourth, in the tape feeder 10 using the sprocket 22, when the tape 2 is first loaded in the tape feeder 10, the tape guide 71 is opened, the teeth of the sprocket 22 are manually inserted into the tape holes 2c, the tape guide 71 is closed, and feeder setting is performed. It is not easy to manually insert the teeth of the sprocket 22 into the tape holes 2c since the teeth of the sprocket 22 and the tape holes 2c of the tape 2 are small. If the teeth of the sprocket 22 are incorrectly inserted into the tape holes 2c, the tape 2 may be incorrectly positioned.
Furthermore, because the top cover discharging unit 40 includes the discharge intermediate gear 59, the discharge worm gear 62, the discharge worm wheel 63, the second roller 64, the first roller 65, the second discharge lever 67, and the second discharge lever spring 67a, the structure is complex and occupies a large space. Additionally, in the case of a large tape feeder, it is difficult to discharge the top cover 2b in a direction orthogonal to a direction in which the tape 2 is fed.
Moreover, since the top cover 2b is removed from the tape 2 only by tension between the first discharge gear 41 and the second discharge gear 42, it is not easy to detach the top cover 2b from the tape 2. As the top cover discharging unit 40 is used repeatedly, a force necessary for pulling the top cover 2b from the tape 2 may be changed, requiring the unit to be maintained and adjusted.